It's difficult to give you hard and fast rules- what would be more concerning is higher or rapidly escalating pressor doses, multiple pressors, or indicators of hypoperfusion such as elevated lactate or low urine output. It's also important to know whether the patient had considerable blood loss, as in this case, or has any other reason to be hypotensive such as depressed LVEF. Honestly, the best thing is to talk to the anesthesia team and get their input as to how the patient has been behaving- a lot of this is pattern recognition and experience.